1. Field of the Invention
The present invention relates to an image reading apparatus and an image reading system.
2. Description of the Related Art
Conventionally, for image reading apparatuses and the like, a technique for detecting edges of sheet-like media has been proposed. Detection of edges enables, for example, detection of a size of a medium.
As a technique for detecting the edges, for example, Japanese Laid-open Patent Publication No. 09-65061 discloses a technique of detecting skewing of an original by providing a reflecting surface having a same reflectivity as that of an original as a background of an original reading portion and detecting a shadow of the original formed on the reflecting surface.
However, when edges of a sheet-like medium are to be detected according to a shadow of the medium, light and shade of the shadow of the medium vary according to the thickness of the medium for example, and accuracy of the detection of edges can decrease according to the thickness or kind of the medium to be detected.